Process of and apparatus for the spinning of cuprammonium filaments



April is, 1935. H, HO MA N 1,9979% PROCESS OF AND APPARATUS FOR THESPINNING OF CUPRAMMONIUM FILAMENTS Filed July 6, 1952 Patented Apr. 16,1935 ATsNr oFwE PROCESS OF AND'APPARATUS FOR THE SPINNING OF MENTSCUPRAMMIONIUM FILA- Hugo Hermann, Johnson City, Tenn, assignor toAmerican Bemberg Corporation, New York, N. Y., a corporation of DelawareApplication July 6, 1932, Serial Nb. 621,101

' 8 Claims.

My present invention has to do with a newand improved method or" anapparatus for the production of artificial threads, filaments andthelike which may be produced by the cuprammonium process.

One object of my invention is to provide a method of coagulating orhardening artificial threads and the like whereby the recovery of theammonia and copper in the coagulating or hardening liquid is madeeconomically possible.

Another object of my invention is to providea new method for thetreatment of cuprammonium thread which will result in a finished productof more even texture and fineness than that produced by existing methodsand mechanisms.

A further object of my invention is to provide a new method of treatingthreads and filaments of cuprammonium silk whereby the strength thereofboth in the wet and in the dry state will be materially improved.

A still further object of my invention is to so treat the threads andfilaments of cuprammonium. silk produced by the stretch spinning processthat disadvantages arising from the formation of eddycurrents will beobviated.

A still further object of my present invention is to so treat thethreads or filaments that the dis-. advantages arising from the. settingup of.cur-. rents of water used in the coagulating or hardening of saidthreads or filaments, which would exert harmful and deleterious injuriesto the more freshly extruded threads or filaments, will be avoided.

These and other objects of my invention will become more apparent from astudy of the following description, and of the drawing, in which:

Figure 1 is a partial sectional View of the spinning mechanism;

Figure 2 is a detailed view of a portion of the funnel; and

Figure 3 is a detailed view of the outlet end of the tunnel of thespinning mechanism.

Referring now more particularly to Figure 1, I have shown a spinneretteill fed with any suitable cellulosic solution, such as a cuprammoniumsolution, by means of the usual feed line (not shown). A double funnelarrangement may be used and, as shown the lower portion of the upperfunnel ii, is within the wall of the lower funnel 812. The upper funnelis enclosed in a casing i3 which has cemented or otherwise securedthereto a flanged. ring M upon which the spinnerette it rests and issuitably secured. A ring i5 is secured to the lower end of said casingwhich is provided with a chamber IS, the upper. wall of which has aseries of openings I"! through which the hardening or coagulating liquidpasses from the inlet/i8.

The. funnel i2 is secured in the ring I 5 by means of any suitablecementitious material 19. To prevent any possible rotation or movementof said funnel, I have provided the same with spaced indentions 29. Atthe lower end of the funnel I have provided an outlet member 2| which issecured to the lower end of the funnel byarubber hose or tube 22. Aswill be noted the upper funnel is provided with anopening 23 by means ofwhich the treating liquid at the upper part of the spinning funnel andsurrounding the spinnerette maybe readily removed.

In the usual operation, the filaments are extruded into a suitablecoagulating solution in the device at the rate of approximately 600 cc.of the solution per minute. This rate of flow has been found necessaryin order to keep the funnel filled with the treating liquid and soprevent the formation of eddy currents which will tend to damage thefreshly spun filaments. The solution, after passing through the funnel,was discarded since only about .8 grams of ammonia was present in each690 cc. of solution. This low concentration made it economicallyimpossible to recoverthe ammonia used. By my new method, however, asiphon action is set up by withdrawing about cc. of the treating liquidthrough the outlet 23' provided in the funnel. The path of movement ofthe treating liquid throughout the spinning chamber has been clearlyindicated by arrows (Figure 1).. I q x The liquid which is thus removedcontains most of the ammonia which is to be recovered, since it is knownthat the greater part of the ammonia of the cuprammonium solution goesinto solution in the coagulating liquid within the area adjacent to andsurrounding the spinnerette. By this .means the treating liquid which isremoved through the above described siphon arrangement will contain ahigh concentration of ammonia ammonia content increases the liquid isrising toward the spinnerette, and those filaments just emergingtherefrom are treated with a liquid which is rich in ammonia and othersalts. As these filaments are very soft and only partially coagulatedthe action of this liquid is very beneficial since a more steady andgradual coagulation action of the filaments takes place. Thus it will beappreciated that by the use of my new method a very gradual and steadyhardening of the filaments will be obtained with the result that thefilaments possess better qualities than those ordinarily produced. Ihave been able also by the use or" this method to obtain a 20% greaterwet strength and a 15% greater dry strength of finished yarn than hasbeen heretofore possible to produce by the cuprammonium stretch spinningprocess.

The ordinary filament possesses a. wet strength of 120 grams per 100denier, and a dry strength of approximately 180 grams per 100 denier. Ihave been able, by my new method and apparatus, to secure a strength upto 144 grams per 100 denier and a dry strength of 207 grams per 100denier.

It will be readily appreciated that I have devised a new method of andapparatus for the production of artificial filaments by which, in thecuprammonium process, the economical recovery of ammonia is madepossible and the resulting product possesses a much greater strengthboth in the wet and dry state.

It is to be understood that numerous details of my new method andapparatus may be varied through a wide range without departing from theterms or spirit of my invention, and I do not desire limiting the patentgranted here or other- Wise than as necessitated by the prior art.

I claim:

1. In the production of cuprammonium filaments, the steps of firstsubjecting the filaments to a setting solution containing a high ammoniacontent of approximately 15 grams of ammonia per 600 cc. of solution,and then toa solution with a progressively lower ammonia content.

2. In the production of cuprammonium filaments, the steps of firsttreating the filaments with a setting solution containing between .8 and20 grams of ammonia per 600 cc., and then subjecting the filaments to asetting bath containing a gradually decreasing ammonia content.

3. In a device for use in the production of filaments by thecuprammonium process, in combination, a spinnerette, a case surroundingthe same, a funnel rigidly fixed in said case and surrounding thespinnerette, and means arranged so that liquid may flow only upwardlythrough the funnel to aid in the precipitation of the filaments and asecond funnel embracing the lower end of said first named funnel.

4. In a device for use in the production of filaments by thecuprammonium process, in combination, a spinnerette, a case surroundingthe same, a funnel rigidly fixed in said case and surrounding thespinnerette, and means arranged so that liquid may flow only upwardlythrough the funnel to aid in the precipitation of the filaments, and asecond funnel embracing the lower end of said first named funnel, theupper end of said second named funnel being itself contained by saidcase.

5. In a device for use in the production of filaments by thecuprammonium process, in combination, a spinnerette, a case surroundingthe same, a funnel rigidly fixed in said case and surrounding thespinnerette, and means arranged so that liquid may flow only upwardlythrough the funnel to aid in the precipitation of the filaments, and asecond funnel embracing the lower end of said first named funnel, theupper end of said second named funnel being itself contained by saidcase, said case being provided with inlet means whereby the settingsolution may enter.

6. In a device for use in the production of filaments by thecuprammonium process, in combination, a spinnerette, a case surroundingthe same, a funnel rigidly fixed insaid case and surrounding thespinnerette, and means arranged so that liquid may flow only upwardlythrough the funnel to aid in the precipitation of the filaments, and asecond funnel embracing the lower end of said first named funnel, theupper end of said second named funnel being itself contained by saidcase, said case being provided with inlet means whereby the settingsolution may enter; said setting solution passing downwardly in saidsecond named funnel and upwardly through said first named funnel.

7 In a device for use in the spinning of cuprammonium filaments, twofumiels arranged above one another so that the upper mouth of the lowerfunnel embraces the lower opening of the upper funnel, and means wherebyliquid may be circulated only downwardly through the lower fruinel andupwardly through the upper funnel.

8. In the production of cuprammonium filaments, the steps of preparing acuprammonium solution and extruding it into a precipitating bathcontaining between 15 and 20 grams of ammonia per 600 cc. of solution.

HUGO HOFMANN.

